In DNA replication, what serves as the template for building new strands?

In DNA replication, what serves as the template for building new strands?

• A. The original DNA strands
• B. The newly synthesized strands
• C. The RNA transcripts
• D. The ribosomes

Answer: (A)

The existing DNA strands act as the template for building new strands. In replication, the double helix unwinds and each original strand guides the synthesis of a new complementary strand, so the two daughter molecules each contain one old and one new strand. DNA polymerases add nucleotides in a 5' to 3' direction by pairing A with T and G with C to mirror the sequence of the template. RNA primers may initiate synthesis, but they don’t serve as the template themselves; the template is still the original DNA strand. The newly synthesized strands are products of the process, not the guide used to assemble them, and ribosomes are involved in translating RNA, not copying DNA, and RNA transcripts relate to transcription rather than replication.

The existing DNA strands act as the template for building new strands. In replication, the double helix unwinds and each original strand guides the synthesis of a new complementary strand, so the two daughter molecules each contain one old and one new strand. DNA polymerases add nucleotides in a 5' to 3' direction by pairing A with T and G with C to mirror the sequence of the template. RNA primers may initiate synthesis, but they don’t serve as the template themselves; the template is still the original DNA strand. The newly synthesized strands are products of the process, not the guide used to assemble them, and ribosomes are involved in translating RNA, not copying DNA, and RNA transcripts relate to transcription rather than replication.